1799439 - Crash in [@ mozilla::dom::RTCRtpTransceiver::ApplyCodecStats::<T>::operator()]

Status: RESOLVED FIXED

(Core :: WebRTC, defect, P2)

Description

[Gabriele Svelto [:gsvelto]]

Crash report: https://crash-stats.mozilla.org/report/index/fef6a2a8-0043-4f67-9d24-a91b90221105

MOZ_CRASH Reason: MOZ_CRASH(Unexpected reject)

Top 10 frames of crashing thread:

0  xul.dll  mozilla::dom::RTCRtpTransceiver::ApplyCodecStats::<lambda_121>::operator const  dom/media/webrtc/jsapi/RTCRtpTransceiver.cpp:1072
0  xul.dll  mozilla::MozPromise<CopyableTArray<mozilla::UniquePtr<mozilla::dom::RTCStatsCollection, mozilla::DefaultDelete<mozilla::dom::RTCStatsCollection> > >, nsresult, 1>::InvokeMethod  xpcom/threads/MozPromise.h:637
0  xul.dll  mozilla::MozPromise<CopyableTArray<mozilla::UniquePtr<mozilla::dom::RTCStatsCollection, mozilla::DefaultDelete<mozilla::dom::RTCStatsCollection> > >, nsresult, 1>::InvokeCallbackMethod  xpcom/threads/MozPromise.h:646
0  xul.dll  mozilla::MozPromise<CopyableTArray<mozilla::UniquePtr<mozilla::dom::RTCStatsCollection, mozilla::DefaultDelete<mozilla::dom::RTCStatsCollection> > >, nsresult, 1>::ThenValue<`lambda at /builds/worker/checkouts/gecko/dom/media/webrtc/jsapi/RTCRtpTransceiver.cpp:1002:17', `lambda at /builds/worker/checkouts/gecko/dom/media/webrtc/jsapi/RTCRtpTransceiver.cpp:1071:17'>::DoResolveOrRejectInternal  xpcom/threads/MozPromise.h:845
1  xul.dll  mozilla::MozPromise<nsTArray<mozilla::net::HttpRetParams>, mozilla::ipc::ResponseRejectReason, 1>::ThenValueBase::ResolveOrRejectRunnable::Run  xpcom/threads/MozPromise.h:487
2  xul.dll  mozilla::RunnableTask::Run  xpcom/threads/TaskController.cpp:538
2  xul.dll  mozilla::TaskController::DoExecuteNextTaskOnlyMainThreadInternal  xpcom/threads/TaskController.cpp:851
3  xul.dll  mozilla::TaskController::ExecuteNextTaskOnlyMainThreadInternal  xpcom/threads/TaskController.cpp:683
3  xul.dll  mozilla::TaskController::ProcessPendingMTTask  xpcom/threads/TaskController.cpp:461
3  xul.dll  mozilla::TaskController::InitializeInternal::<lambda_4>::operator const  xpcom/threads/TaskController.cpp:187

I found this while triaging nightly builds but it appears to be an existing issue.

Comment 1

[Byron Campen [:bwc]]

I am not sure how we're ending up in the promise rejection code when we're starting from here: https://hg.mozilla.org/releases/mozilla-release/file/eecea05aff4d09b70d13842a8e07160f04ac0349/xpcom/threads/MozPromise.h#l845

I think the line number must be incorrect here.

Additionally, I don't see any way for this Promise chain to reject here:
https://hg.mozilla.org/releases/mozilla-release/file/eecea05aff4d09b70d13842a8e07160f04ac0349/dom/media/webrtc/jsapi/RTCRtpTransceiver.cpp#l1070

... especially considering that we did not reject in the previous promise in the chain here:
https://hg.mozilla.org/releases/mozilla-release/file/eecea05aff4d09b70d13842a8e07160f04ac0349/dom/media/webrtc/jsapi/RTCRtpTransceiver.cpp#l994

Comment 2

[Byron Campen [:bwc]]

I guess |allPromise| here must be rejecting?

https://hg.mozilla.org/releases/mozilla-release/file/eecea05aff4d09b70d13842a8e07160f04ac0349/dom/media/webrtc/jsapi/RTCRtpTransceiver.cpp#l991

Comment 3

[Byron Campen [:bwc]]

Maybe we should not be rejecting here?

https://searchfox.org/mozilla-central/source/dom/media/webrtc/jsapi/MediaTransportHandlerIPC.cpp#351-354

Also, I'm not sure what happens here when mInitPromise rejects, since there's no reject function:

https://searchfox.org/mozilla-central/source/dom/media/webrtc/jsapi/MediaTransportHandler.cpp#1278

We probably want to modify both of these to resolve with an empty RTCStatsCollection on rejection.

Comment 4

[Byron Campen [:bwc]]

https://treeherder.mozilla.org/jobs?repo=try&revision=cf74e58576968629269567c1d49258a061501eb8
https://treeherder.mozilla.org/jobs?repo=try&revision=474a98612ceb1f4c4c06a988893861ece73e8506

Comment 5

[Byron Campen [:bwc]]

Attachment: Bug 1799439: Don't reject in GetIceStats. r?mjf

Comment 6

[Byron Campen [:bwc]]

Try looks normal.

Comment 7

[Byron Campen [:bwc]]

We don't have repro steps, and are therefore not sure this will fix the issue, so marking leave-open. We'll have to keep an eye on crash-stats to see if this resolves after landing.

Comment 8

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/3f107a501d2c
Don't reject in GetIceStats. r=mjf

Comment 9

[Natalia Csoregi [:nataliaCs]]

https://hg.mozilla.org/mozilla-central/rev/3f107a501d2c

Comment 10

[Byron Campen [:bwc]]

The crashes on nightly seem to have stopped.